/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.datashark.service.utils;

import com.datashark.common.constants.Constants;
import com.datashark.common.constants.DataSourceConstants;
import com.datashark.common.utils.PropertyUtils;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang3.StringUtils;

import java.net.URL;
import java.nio.charset.StandardCharsets;

import lombok.extern.slf4j.Slf4j;

/**
 * common utils
 */
@Slf4j
public class CommonUtils {

    private static final Base64 BASE64 = new Base64();

    protected CommonUtils() {
        throw new UnsupportedOperationException("Construct CommonUtils");
    }

    /**
     * @return get the path of system environment variables
     */
    public static String getSystemEnvPath() {
        String envPath = PropertyUtils.getString(Constants.datashark_ENV_PATH);
        if (StringUtils.isEmpty(envPath)) {
            URL envDefaultPath = CommonUtils.class.getClassLoader().getResource(Constants.ENV_PATH);

            if (envDefaultPath != null) {
                envPath = envDefaultPath.getPath();
                log.debug("env path :{}", envPath);
            } else {
                envPath = "/etc/profile";
            }
        }

        return envPath;
    }

    /**
     * encode password
     */
    public static String encodePassword(String password) {
        if (StringUtils.isEmpty(password)) {
            return StringUtils.EMPTY;
        }
        // if encryption is not turned on, return directly
        boolean encryptionEnable = PropertyUtils.getBoolean(DataSourceConstants.DATASOURCE_ENCRYPTION_ENABLE, false);
        if (!encryptionEnable) {
            return password;
        }

        // Using Base64 + salt to process password
        String salt = PropertyUtils.getString(DataSourceConstants.DATASOURCE_ENCRYPTION_SALT,
                DataSourceConstants.DATASOURCE_ENCRYPTION_SALT_DEFAULT);
        String passwordWithSalt = salt + new String(BASE64.encode(password.getBytes(StandardCharsets.UTF_8)));
        return new String(BASE64.encode(passwordWithSalt.getBytes(StandardCharsets.UTF_8)));
    }

    /**
     * decode password
     */
    public static String decodePassword(String password) {
        if (StringUtils.isEmpty(password)) {
            return StringUtils.EMPTY;
        }

        // if encryption is not turned on, return directly
        boolean encryptionEnable = PropertyUtils.getBoolean(DataSourceConstants.DATASOURCE_ENCRYPTION_ENABLE, false);
        if (!encryptionEnable) {
            return password;
        }

        // Using Base64 + salt to process password
        String salt = PropertyUtils.getString(DataSourceConstants.DATASOURCE_ENCRYPTION_SALT,
                DataSourceConstants.DATASOURCE_ENCRYPTION_SALT_DEFAULT);
        String passwordWithSalt = new String(BASE64.decode(password), StandardCharsets.UTF_8);
        if (!passwordWithSalt.startsWith(salt)) {
            log.warn("There is a password and salt mismatch: {} ", password);
            return password;
        }
        return new String(BASE64.decode(passwordWithSalt.substring(salt.length())), StandardCharsets.UTF_8);
    }

}
